I know the usual demand and supply bit [0]. I need help in understanding how a stock trading at $25 goes to $26 or $24.
[0] https://www.investopedia.com/ask/answers/12/how-are-share-prices-set.asp
These are the guys that "make the market". It's their job to buy and sell the shares they manage (are market makers for).
This is why you can open an order for stock X and always get filled -- it's at the price _they_ set.
This means you don't have to wait (for days/weeks?!) for a buyer/seller for that block of shares you want to sell/buy -- you buy/sell them to a market maker and they take it from there.
These guys run a "book" of orders and it's based on this that they offer prices, their goal is to have a balanced book and not be overtly long or short a particular stock, but they do for certain periods of time (think during the day's open trading session).
In practice you'll discover that MMs have ultimate power is guiding a stock's price, they can hold buys and sells until it's optimal for them.
Essentially, you're not competing against other buyers/sellers in a free open market, but against MMs who hold all the cards.
will the stock price tick to $50 for that one transaction ?
To match buyers with sellers